Colorimetric Sensing of Fluoride Ion by New Expanded Calix[4]pyrrole through Anion−π Interaction

Abstract

Three new expanded calix[4]pyrroles were synthesized, where the two dialkylldipyrromethane units are linked via C-C double bonds. One of them, calix[2]bispyrrolylethene, colorimetrically senses fluoride ion only, owing to anion-π interaction in polar aprotic solvents.

A Tetrapyrrole Macrocycle Displaying a Multielectron Redox Chemistry and Tunable Absorbance Profile

“…Fluoride binding to expanded porphyrinoids 37–39 and porphyrinogens 40 is well established, and similar behavior has been reported for binding of fluoride to an expanded calix[4]pyrrole. 41 Job analysis of fluoride binding clearly demonstrates that Phl F is capable of binding up to two F – ions (Figure S5) to generate 3H(Phl F )·2F – . This binding stoichiometry is uncommon for simple tetrapyrrole platforms, however allosteric fluoride binding has been reported for a doubly strapped porphyrin containing two discrete anion-binding pockets.…”

New dimensions in calix[4]pyrrole: the land of opportunity in supramolecular chemistry

“…It has also been observed from the literature that the strapped system 5 has inherent advantages over the deep cavity system 4. [33][34][35][36][37][38][39] We are fairly certain that once the synthesis of 6 is achieved, it will denitely provide a new dimension to the C4P chemistry.…”

First phenalenone based receptor for selective iodide ion sensing

“…The receptor was tested for anion sensing because it has two probable anion interaction sites such as NH ( N H -anion hydrogen bond interaction; marked as red circle) and phenalenone (C H -anion hydrogen bond interaction or anion -charge transfer interaction; marked as green square in Scheme 1). These interactions are observed in many published chemosensors including few pyrrole based molecules [11,12].…”